Introduces the two value types (Frame, Position) that represent retail's
cell-relative position pair (acclient.h:30647/30658). Types are unused
by consumers yet — zero behavior change. Also ports LandDefs::get_block_offset
(pc:69189, @0x0043e630): world-meter offset between two named landblock ids,
the ONLY cross-cell translation primitive in retail physics. Conformance tests:
same-landblock→Zero, south-neighbour→(0,-192,0) (the exact #145 cascade cell),
east-neighbour→(+192,0,0), diagonal→(+192,+192,0). 4/4 pass; full Core suite
1522 passed / 0 failed. DatFrame alias added to 4 files that had using
DatReaderWriter.Types + using AcDream.Core.Physics in scope simultaneously.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Pure function translating Setup -> IReadOnlyList<ShadowShape>. Walks
CylSpheres + Spheres (only when no CylSpheres) + Parts (only when the
GfxObj has a non-null PhysicsBSP), using PlacementFrames in the same
Resting -> Default -> first-available priority as SetupMesh.Flatten.
Six tests pin the behavior: door setup produces 4 shapes (0+1+3), sphere
local offset matches Setup data, parts without BSP are skipped, creature
setups with CylSpheres skip Spheres, scale factor multiplies all radii
and offsets, empty setup returns empty list, null setup throws.
No callers in this commit; RegisterMultiPart + the GameWindow callers
follow.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
